An organic polymer and a curable composition each having an alkoxysilyl group having reactivity have already been industrially produced and merchandised, and have been widely used in applications such as an adhesive, a sealing material, and a paint. A method involving polymerizing a compound having a polymerizable unsaturated bond and an alkoxysilyl group, and a vinyl-based monomer has been conventionally known as a method of synthesizing an organic polymer having an alkoxysilyl group, and a (meth)acryloxypropylpolyalkoxysilane such as methacryloxypropyltrimethoxysilane has been used as the compound having a polymerizable unsaturated bond and an alkoxysilyl group (Patent Document 1).
Such curable composition is typically cured with any of various metal catalysts, and has been used for assorted applications depending on the kinds of the catalysts and whether the addition amounts thereof are large or small. However, such conventional curable composition has had difficulty in achieving compatibility between curability and toughness. Further, the metal catalysts generally used in those applications, which are organotin compounds, may each contain a highly toxic tributyltin derivative, and hence a concern has been raised about the toxicity.
Meanwhile, as described in Patent Document 2, there exists a polymer having an alkoxysilane terminal having such high reactivity that the content of a tin-containing catalyst can be significantly reduced. Among the contents reported in the literature is, for example, a report that a catalyst containing tin and any other heavy metal can be removed. However, the polymer having an alkoxysilane terminal described in Patent Document 2 is problematic in terms of its storage stability, though the polymer is excellent in curability. Accordingly, a problem arises upon production of an industrial product from the polymer.